The goal of the current research is to study the effect of cooperative learning method on the academic progress of mental Retardation students. For this study, 38 mental Retardation students in the fifth grade from among exceptional schools in the city of Tabriz were randomly selected and were put into two test and control groups. Before the start of the program, an intervention was conducted using the cooperative learning method. The academic progress test made by the researcher was conducted as a pretest for both groups. Then, the prepared program was taught in Ten 45 minute sessions to the test group using the cooperative learning method and the traditional method was used for the controlled group. After the end of teaching the sessions, the academic progress test made up by the researcher was once again administered for both groups as the post test. The data was analyzed using the covariance statistical test. The results show that cooperative learning has been effective in the academic progress of mentally Retardation students.